Suspension and or shock-absorbing device for a support arm of a vehicle wheel

Abstract

Suspension and/or shock-absorber device of a rotary support arm of a vehicle wheel such as the rear wheel of a motorcycle, comprising disposed on one side of the support arm, a three arms lever mounted rotary-wise on a lever axle integral with the chassis of the vehicle and a short arm of which is connected in rotation to the body of a suspension and/or shock-absorber block with rods which are movable in translation, the device being applicable to a suspension utilizing a shock-absorbing spring block disposed underneath the engine block.

I claim: 
     
       1. A suspension and shock-absorbing device for a support arm of a wheel of a motorcycle, said support arm pivotally mounted at one end thereof to a connecting axle secured to a body of said motorcycle, said device comprising: a lever axle being secured to said body and being substantially parallel to said connecting axle;   a three arm lever rotatably mounted on said lever axle, said three arm lever including a medium arm, a short arm substantially opposite the medium arm and a long arm directed toward the wheel of said motorcycle;   said support arm including an extension adjacent said connecting axle;   a short push-rod hingedly connecting said medium arm of said three arm lever to said extension;   a spring suspension and damper unit having a movable rod in translation;   said short arm of said three arm lever pivotally connected to said spring suspension and damper unit;   a medium push-rod hingedly connecting the long arm of said three arm lever to the movable rod of said spring suspension and damper unit;   a long push-rod pivotally connected at one end to said movable rod of said spring suspension and damper unit and at an opposite end to said support arm at a position adjacent said wheel so as to provide a scissor-like hanging of the spring suspension and damper unit with respect to the short arm of said three arm lever and to provide a pivotal connection of the movable rod to the medium and long push-rods.   
     
     
       2. A device according to claim 1, wherein the lengths of the arms of the three-arm lever, the position of the lever axle with respect to the connecting axle, and the lengths of the short, medium and long push-rods and the position of hinging axles thereof, are selected so that the movable rod of the spring suspension and damper unit remains substantially parallel to the rolling surface of the wheel during suspension displacement of the support arm. 
     
     
       3. A device according to claim 1, wherein said motorcycle includes an engine transmission block, and wherein the spring suspension and damper unit is principally housed underneath the engine transmission block, and the short arm of the three-arm lever is hinged to the engine transmission block and is connected to the spring suspension and damper unit in the vicinity of the hinged connection to the engine transmission block. 
     
     
       4. A device according to claim 1, wherein the medium push-rod and the long push-rod are hinged to the movable rod of the spring suspension and damper unit. 
     
     
       5. A device according to claim 1, further including a connecting piece fixedly connected with the movable rod, and wherein the medium push-rod and the long push-rod are hinged together to the movable rod of the spring suspension and damper unit by connecting piece. 
     
     
       6. A device according to claim 5, wherein said motorcycle includes a brake calliper bracket plate receiving a brake reaction torque of the wheel and intended to turn angularly around the axle of the wheel during displacement of the connecting piece and a retaining rod hinged at one end to said bracket plate, and wherein said connecting piece is hinged to an opposite end of said retaining rod. 
     
     
       7. A device according to claim 1, wherein, in a position of maximal extension of the movable rod with respect to the spring suspension and damper unit block, the long push-rod is inclined at an angle of essentially 45° with respect to the support arm.